Deaeration and drying of watersoluble sulfonated detergent compositions



Aug. 5, 1952 2,606,156

E. DAVIS DEAERATION AND DRYING OF WATER-SOLUBLE SULFONATED DETERGENTCOMPOSITIONS Filed June 9, 1950 MIXER EUTRALIZER AERATOR RECEIVYER WEIGHTANKS SPRAY DRYER IN V EN TOR.

Patented Aug. 5, 1952 DEAERATION DRYING OF WATER- SOLUBLE SULFONATEDDETERGENT I ccnrosmoss EarliDavis, Whittier, Calif., assignor t01PurexCorporation,,Ltd South Gate, Calif., a combration of- CaliforniaApplicatieniune 9, 1950, Serial No. 167,086

9 Claims- (c1; 2s2- -1c1) This invention has to do generall with themanufacture of detergents suitable for use as washing compounds, andparticularly with the production of such compounded detergents bymethods having for" their major object to give to the final andmarketable products d'esirablesolm bility properties and high bulkdensities. While applicable broadly to the manufacture ofdetergentcompositions ingeneral and whose densities are subfiect to increase bydeaeration of a dry'able slurry containing the detergent, the inventionwill be described typically, though as illustrative only, with referenceto detergents containing as active ingredients the alkali metal salts oforganic 'sul- -fonates and sulfates having such molecular structuresas'to possess detergent properties.

It has been customary the manufacture-of such detergents toproduce'firs't an aqueous slurry of the alkali metal organic sulfonatesor sulfates, to which are added one or more salts or additives such assoda ash, sodium bicarbonate, alkali metal silicate, borax, sodiumsulfate, sodium chloride, fullers earth and the like, to produce amixture orslurr-y dr'yaole to any final form, e. g. as by spray drying,drum'drying, or tray drying. Considering spray drying as typical,- it isdesirable that the solidgranules resulting from spray drying of theslurry, have a high bulk density, say upward of 0.40or above. Now by theusual methods of slurry treatment. and dehydration, potentially highbulk densities of final product either are not obtainable, or can bereached only as a result of relatively inconvenient and prolongedprocedures. V

7 It is found that lower densities of the final product generally are.due to the presence of air in the mixture or slurry to be dried, and tothe retention of the air in the dried product, as in the case of spraydried granules wherein the entrapped air tends to expand the particlesand therefore lower their bulk density. My general object is toprovide asimple and emiently practical method-whereby in continuous operation anaeratedslurry may be quickly and efiectively deaerated to the degreedesired, and the deaerated slurry thenvdehydrated and dried, as by afinal spray drying operation. I

- In accordance withthe invention, a slurry containing any suitablealkali metal sulfonates orsul fates possessing detergent properties,(for example as more fully developed in a copending Stoneman applicationSerial Number 167,642,

.filed' June 12, 1950), may be mixed with any of such solid additives asthe -builders and fillers referred toabove, Merely as illustrative, the

organic detergent components of the slurry may include or consist ofcompounds of the general formula R,SO2-OH, wherein R. is any benzenoidhydrocarbon radical having two or more replaceable nuclear hydrogenatoms (as derived frombenzene, toluene or xylene), and at least onenuclear hydrogen atom replaced by aliphatic or alicyclic radicalcontaining 8 to 18 carbon atoms. Examples are the alkali metal salts ofn-dode'cyl benzene sulfonic acid, n-dodecyl toluene sulfonic acid,undecane-Z-benzene sulfonic acid, and in generalv mixtures of this classin which t s a is; c r on alkyl radical isderived frorn aliphatic oralicyclic compounds of either straight or branched, symmetrical ornon-symmetrical structure, such as may be foundin ledpetroleum fractionsor in other naturally H I, 7 ng substances. Other contemplated detergetsmentioned also in the Stoneman application) include the sultonic andsulfuric acid derivatives ofthe 8-18 carbon atoms olefins, alcohols,fatty acids, alkyl halides, and esters in the alipha-te or alicyclicseries and mixtures thereof, Generally, the slurry to be deaerated priorto. drying rnay be characterized with respect; to its 3 active contentas containing an .lanionic or mixture thereof, in the class of organic,sultonates or sulfates containing an aliphatic or iiJiQYQli? ar W 5K 3m b attached to an aromatic ring, with the aliphatic or alipart beingderived irorn compounds contai-ning 8-13 carbonatoms and capableofeither direct reaction to the sulfates or sulfonates, or indirectreaction by combination with an aromatic ring part or radical.

Deaeration of the slurry preparatoryto drying,

is accomplishedby passingthe slurry through azone maintained undersubatmospheric pressure and within a range that may be regulated inaccordancewith the degree of deaeration desired. Typically, thedeaeration chamber is main- ;tained at an absolute pressure within therange of about to 250 mm. As will appear, the invention contemplates anuninterrupted process wherebythe admixed slurry and additives may bepassedcontinuously from the mixer and .thencethrough the deaerator tothe spray drier.

mar object-of the invention is to make higher density final productsfrom a slurry pro duced bythe method of my copending applicationreferred to above, accordance with which the I alkalimetalorganicsulfonate results from neutralizationunder low pressure andunder conditionssueh that the neutralized slurry going into the mixer,has been subjected to eiiective preliminary deaeration. When operated inconjunction with this low pressure process of neutralization, the bulkof the air removed in the final deaeration stage is that introduced intothe slurry in the mixing operation.

All the features and objects of the invention, as well as the details ofan illustrative embodiment, will be more clearly understood from thefollowing detailed description of the accompanying drawing illustratinga typical procedure diagrammatically and in flow sheet form:

While it is to be understood that in the broad contemplation of theinvention, the slurry to be subjected to final deaeration preliminary todrying, may be produced in any suitable manner, there are advantages inso treating a slurry which has been subjected to prior deaeration duringand as a result of a low pressure neutralization stage. For morecomplete details concerning the low pressure neutralization of asuitable sulfated or sulfonated detergent stock, reference may be had tothe copending Stoneman application referred to above. For presentpurposes, it will suflice to refer to the neutralizing stage, generallyindicated at H], as comprising a neutralizing chamber ll evacuatedthrough head [2 connecting with a vacuum pump or steam ejector tomaintain in the chamber an absolute pressure within the range of about 9to 88 mm. of mercury and at a corresponding water vapor temperaturerange between about 50 to 120 F.

Chamber ll communicates through line 13 with one or the other of theclosed weigh tanks 15 and i 6 which, should line 13 form a direct andunrestricted passage, are located below the neutralizer a distance suchthat the communication between the neutralizer and tank constitutes abarometric leg. This distance may be shortened by placing in line I3 apump 11, the displacement rate of which is suflicient to permitmaintenance of the stated low pressure in the neutralizer. At the startof the neutralizing operation, one or the other of the tanks 15 and I6is charged with a weighed quantity of alkali, preferably caustic sodasolution, a stream of which is constantly circulated through line II! bypump 18 into a header I9 communicating with circularly arranged spraynozzles 20 in the head of the neutralizing chamber. The sulfonatedhydrocarbon stream is fed at a predetermined rate through line 2| into asecond header 22 which also connects with the spray nozzles 20. Thesulfonic acids and alkali are premixed, reacted and sprayed into theneutralizer, and the resulting solution or slurry is taken through linel3 to the weigh tank. This cycle of alkali and slurry recirculation fromthe tank to the spray nozzles continues until a predetermined andstoichiometric quantity of the acids is neutralized by reaction with thealkali in the neutralizer. The neutralized slurry finally is withdrawnfrom tank l or 16 through line 24 for delivery to the mixer 25.

Suitable solid builders or flllers are added through inlet 26 to theslurry in the mixer and the components are subjected to thorough mixingas by a mechanically driven agitator diagrammatically indicated at 21.From typical operating data, it is found that the specific gravity ofthe neutralized slurry going to thei mixer may be within the range ofabout 0.84 to 1.14. The sulfonated slurry after compounding with theadditives in the mixer and containing for example 8 to 27 by weight ofthe neutralized active detergent, has an increased density with-' in therange of about 1.15 to 1.20. This slurry then is continuously withdrawnfrom the mixer through line 28 and discharged by pump 29 into adeaerating chamber 30 preferably in flnely divided or sprayed form, asthrough a spray nozzle 3| in the head of the chamber. The latter isconnected through line 32 with a suitable evacuator, so that thedeaerator is operated under a pressure considerably below atmosphericpressure, and typically within the range of 50 to 250 mm. absolute.Ordinarily the temperature of the compounded slurry will beapproximately atmospheric temperature. Being dispersed in finely dividedform within the evacuated zone, the compounded slurry is effectivelydepleted of its air content, as well as some moisture, in accordancewith the pressure existing in the deaerator, and its density is broughtwithin the range of say 1.20 to 1.44.

The deaerated slurry is continuously withdrawn from the deaeratorthrough line 33 and is discharged by pump 34 into a suitable drier 35,preferably of the spray type within which the slurry is reduced tofinely divided form and dried by contact with hot gases or air,resulting in the production of the detergent as granulized particles. Aspreviously indicated, the primary effect and advantage of the deaerationis the production of granules having higher bulk densities, thisproperty apparently being due to the fact that whereas ordinarily thepresence of air in the slurry being spray dried tends to remainentrapped and to expand therein, thus enlarging the hollow globularparticles and thinning the shells, preliminary removal of the air in ac-;-to produce the detergent in solid form.

2. The method of producing an increased density detergent of the classconsisting of synthetic anionic sulfated and sulfonated water solubledetergents, that comprises subjecting an air-containing fluid aqueousslurry of the detergent to deaeration, without drying at an absolutepressure between about 50 to 250 mm. of mercury in one zone, and thendrying the deaerated fluid slurry in another independent zone to producethe detergent in solid form.

3. The method of producing an increased density detergent from anair-containing fluid slurry thereof of the class consisting of syntheticanionic sulfated and sulfonated water soluble detergents, that comprisesdeaerating, without drying the slurry by' dispersing the slurry individed and extensively exposed surface within a zone maintained atsubatmospheric pressure. continuously withdrawing the deaerated slurryfrom said zone into a second zone, and then spray drying the fluiddeaerated slurry in said second zone to produce the detergent in solidgranular form. a

4. The method of producing an increased density detergent of the classconsisting of synthetic v anionic sulfated and sulfonated water solubledetergents, that comprises mixing solid additives with and therebyentraining air in an aqueous slurry of the detergent in a first zone,subjecting the resulting mixture to deaeration and partial dehydration,but without drying, at subatmospheric pressure in a second zone bydispersing the slurry in extensively exposed surface form into theevacuated atmosphere of the second zone and then spray drying thedeaerated mixture in a third independent zone.

5. The method of producing an increased density detergent of the classconsisting of synthetic anionic sulfated and sulfonated water solubledetergents, that comprises mixing solid additives with and therebyentraining air in an aqueous slurry of the detergent in a first zone,subjecting the resulting mixture in divided and extensively exposedsurface form to deaeration, without drying at an absolute pressurebetween about 50 to 250 mm. of mercury in a second zone, and then spraydrying the deaerated mixture in a. third independent zone.

6. The method of producing an increased density detergent of the classconsisting of synthetic anionic sulfated and sulfonated water solubledetergents, that comprises mixing solid additives with and therebyentraining air in an aqueous slurry of the detergent in a first zone,deaerating the mixture, without drying it, by spraying a, slurry of themixture within a second zone maintained at subatmospheric pressure, andcontinuously withdrawing and spray drying the deaerated slurry in athird independent zone.

'7. The method of producing an increased density product detergent froman aqueous slurry of an alkali metal alkyl aryl sulfonate detergent.that includes mixing solid additives with said slurry in a first zoneunder conditions tending to aerate the slurry and thereby producing anaerated slurry having a density between about 0.95 to 1.20, deaerating,Without drying, said aerated slurry in a second zone to a degreeincreasing its density to within the range of about 1.20 to 1.44, andfinally spray drying the deaerated slurry in a third independent zone.

8. The method of producing an increased density detergent product from adetergent of the class consisting of alkyl aryl sulfonates having abenzene radical to which is attached an aliphatic radical containingbetween 8 to 18 carbon atoms, that includes mixing solid additives withan aqueous slurry of the detergent in a first zone under conditionstending to aerate the slurry and thereby producing an aerated slurryhaving a density between about 0.5 to 1.20, deaerating, without drying,said aerated slurry in a second zone to a degree increasing its densityto within the range of about 1.20 to 1.44, and finally spray drying thedeaerated slurry in a third independent zone.

9. The method of producing an increased density product detergent of theclass consisting of synthetic anionic sulfated and sulfonated watersoluble detergents from an aqueous slurry thereof that,includes mixingsolid additives with said slurry in a first zone under conditionstending to aerate the slurry, continuously discharging the seratedslurry through a second zone maintained at subatmospheric pressure below250 mm. absolute pressure and therein removing the bulk of the aircontent of the slurry without drying the slurry, continuously pumpingthe deaerated slurry from the second zone into a third zone, and spraydrying the slurry in the third zone to convert the slurry to dry granulized particles.

1 EARL DAVIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 19,456 Clayton Feb. 12, 19351,414,015 Godfrey Apr. 25, 1922 2,084,446 Lorenz June 22, 1937 FOREIGNPATENTS Number Country Date 61,127 Great Britain 1899

1. THE METHOD OF PRODUCING AN INCREASED DENSITY SOLID DETERGENT OF THECLASS CONSISTING OF SYNTHETIC ANIONIC SULFATED AND SULFONATED WATERSOLUBLE DETERGENTS, THAT COMPRISES SUBJECTING AN AIRCONTAINING FLUIDAQUEOUS SLURRY OF THE DETERGENT